This invention relates to a method and apparatus for the collection and defibrination of blood in flexible containers.
It is well known that is is necessary to take action either during or immediately after the collection of blood to prevent clotting of the blood. One such ction is the addition of anticoagulant drugs or chemicals to the blood. While the addition of these additives is effective to prevent the blood from clotting, there are instances where blood containing these additives may not be used; i.e., in the preparation of blood agar plates used in microbiology. In such instances it is necessary to defibrinate the blood. The term defibrination refers to a method to prevent blood from clotting after it is withdrawn from the donor without the addition of any chemical additives to the blood.
One procedure heretofore used to defibrinate blood utilizes beaters to whip the blood and thereby remove the fibrin necessary for clotting. Another heretofore used procedure utilizes a glass or other rigid material container to collect the blood. A sufficient amount of glass beads, marbles, metallic balls, or other formed elements or the like are placed in the rigid container. As the blood is being drawn into the container, the container is continuously shaken in a manner which agitates the glass beads or substitutes through the blood for a specified time sufficient to whip out the fibrin. In order to obtain the necessary whipping action of the beads within the blood, the container can only be about half full of blood. The reason for this is that the beads will move sluggishly through a container full of blood, but will move rapidly through a container half full of blood. This movement of the beads is most important since the speed of defibrination is essential if clotting is to be prevented.
While the above method of defibrination when performed properly prevents the clotting of the blood it has two serious drawbacks. Firstly, it requires the use of glass or other rigid material bottles and glass beads or the like. The bottles and beads must be sterilized for additional reuse. Such sterilization procedures are not only costly and time-consuming, but sometimes results in cross-contamination. Moreover, the use of glass bottles has often been found to be somewhat of a hazard, due to breakage and dripping problems. In other applications glass bottles have been replaced by flexible, disposable plastic containers. However, since the side walls of a half full flexible container collapse around the contained fluid, by merely substituting a flexible container for the glass bottle it has heretofore not been possible to attain the necessary movement of the beads through the collected blood. Secondly, the rigid container can only be approximately half filled with blood. This results in either the increase in bottle size or the use of additional bottles to collect a fixed amount of blood.